Props

[Dave B]

Thanks again for the compliment. It was easy and fun to make, it's lighweight and could be shaped to any form. The foam disks and plywood were cut with a router and urathane glue was used to bond it all together before turning it to shape. A simple "T" nut was hammered in the center on the backside of the plywood before gluing the foam together and a machine bolt with nut threaded onto it from the outside made for the shaft to be chucked into my hand drill. I just held the drill against the bench top and ran it at slow speed and turned it to shape with a surform rasp, (wear a mask). I could do this again easily in less than a couple hours. I'd like to see someone else do this and post their photos and comments too.  Dave B.

[aeroenergy]

You can of course also try to buy these blades of the shelf:

http://www.fieldlines.com/story/2005/11/28/144711/76

[willib]

Those look to have a pretty agressive pitch at the tip ?

if you draw a line down the trailing edge , it seems that they could/should? be wider near the hub

[theTinker]

"The wife was tired of sanding..."     ---  a classic

[Dan 04617]

There are some beautiful pictures of spinners here and some interesting discussion.  Thank you.

My understanding of aerodynamics is that the windward face isn't as important as the trailing part.  Navy torpedo tests found that there was virtually no difference between a hemispheric front face and one that had the center 50% made as a flat plate.  Wing leading edges are relatively blunt, but trailing edges are sharp.  

Spinners may increase air to the blades and increase power, but to reduce drag and force on the tower, should we be concentrating on a trailing cone rather than a spinner?  It's more tricky with a tail that pivots to furl though.

[willib]

Which urethane glue did you use?

this is a link to 3M urethane adhesives

http://multimedia.mmm.com/mws/mediawebserver.dyn?NNNNNNwuFZaNgqON9qONNN3S_yJmmmml-